The present invention generally relates to a heater system, and more particularly, to a heater system having improved fuel delivery and heat extraction systems.
Conventional heaters burn fuel to produce thermal energy or heat, which is usually used for heating air and/or water. Various fuels are burned, but biofuels have become increasingly popular. Solid biofuels include organic materials such as sawdust, wood chips, and other plant materials (e.g., corn husks). These biofuels are desirable because they are byproducts of industry. For example, sawdust and wood chips are readily available at sawmills and furniture manufacturers and provide a low-cost heating source. Plant materials are readily available at farms and nurseries and also may be used for heating. Other solid biofuels such as dried animal waste may also be available as fuel to provide heat.
Conventional heaters often include a stoker or fuel delivery system for delivering the selected fuel to a combustion chamber or combustor where the fuel is burned to produce heat. Fuel delivery mechanisms include conveyor belts, chutes, and augers. The burning fuel is supplied with air to provide oxygen needed to burn the fuel. In some cases, a blower forces air past the burning fuel to feed the fire. The resulting gases are vented through a vent pipe or exhaust vent extending from the combustor. Ash and residual solid materials are also removed, e.g., by gravity, to clear the combustor for further biofuel delivery.
Although these systems provide inexpensive heat, there are issues which limit their effectiveness. For example, the fuel delivery mechanisms may not be dependable. The fuels may stop flowing (e.g., due to rat holing or arching as will be explained below), thereby starving the fire. In other instances, the fuel delivery mechanism continues to feed fuel to the combustor after the fire goes out. Before the fire can be relit, the excess fuel must frequently be removed from the combustor.
Many heaters incorporate heat exchangers to capture heat from the system for heating air, water, or other fluids. Some prior heaters have heat exchangers that cause inefficient fuel burning, which results in excessive smoking and soot build up. In some heaters, heat fluctuates significantly with changing conditions, providing an undependable heat source and operating temperatures outside desirable working ranges. Thus, there remains a need for heater improvements that capture heat for warming air, water, and other fluids.